Air filtration device including filter change indicator

ABSTRACT

An air filtration device for intake of atmospheric air, removal of contaminants from the atmospheric air, expulsion of filtered air, includes a housing configured for application directly to an electrical outlet and provides air intake from the front surface of the housing and air expulsion from the side of the housing to utilize a wall surface to disperse the filtered air. A filter change indicator is provided to communicate that a filter should be changed, and a filter orientation system is provided to allow proper orientation of the filter with respect to air flow.

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application is a continuation-in-part of copending U.S.patent application Ser. No. 09/563,821, filed May 3, 2000.

BACKGROUND OF THE INVENTION

[0002] The present invention related broadly to air filtration apparatusand, more particularly, to an air filtration device that is configuredfor abutment against an electrical outlet providing operational powerfor the device, with atmospheric air flowing into an intake on the frontsurface of the device, and filtered air being emitted through ventsprovided on the side of the device.

[0003] As the atmosphere in general becomes more polluted and thegeneral population becomes more aware of discomforts associated withdirty air, air filtration devices of all shapes, types and sizes havebecome more popular. One type of air filtration device provides a smallfan for use in a smoky environment. These devices typically will includean electric fan contained in a small housing for tabletop use, with afilter through which the air is directed for removal of smoke and othersuch contaminants. These small fans are useful for removing odors andcontaminants from a confined space, since they typically take up littlespace themselves and move a relatively small volume of air.

[0004] Such current designs, while effective, leave room for improvementin the areas of noise control, air dispersion and filter management.

SUMMARY OF THE INVENTION

[0005] An air filtration device is provided for intake of atmosphericair, assistance in removal of contaminants from the atmospheric air,expulsion of filtered air and configured for operational associationwith a generally vertically oriented surface. The device includes ahousing defining an air flow path therethrough having a front surface,at least one side surface and a rear surface; at least one air inletformed in the front surface of the housing; and at least one air outletformed in the housing intermediate the front surface and the rearsurface, for cooperation of the air outlet with a generally verticalsurface to which the air filtration device is associated for enhanceddispersion of filtered air expelled through the air outlet. A filter ismounted to the housing in the air flow path and an impeller is providedfor moving air through the housing along the air flow path from the atleast one air inlet to the at least one air outlet, with the impellerbeing mounted to the housing.

[0006] The air outlet may be formed on the at least one side surface andthe air flow path may be defined from the air inlet on the front surfacethrough the filter, through the impeller and outwardly through the airoutlet. Also, the side surface may be curved and the air outlet may beformed as a series of vents along the curvature of the side surface.

[0007] The air filtration device may further include a bumper memberattached to the rear surface of the housing for abutment with agenerally vertical surface to which the air filtration device isassociated for orientation of the device with the vertical surface. Thebumper member may also be formed from resilient material for enhancednoise reduction when the air filtration device is in operation. Thefilter can be formed as a generally planar member selectively removablefrom the housing and can include a notch formed therein for directinginsertion of the filter in a correct orientation with respect to the airflow path. The housing may include a locating surface formed thereon andcorresponding with the notch in the filter to orient the filter in thehousing. The housing may also include an icon formed thereon at aposition corresponding with the notch in the filter when the filter isinserted in the housing for enhanced visual indication of proper filterorientation.

[0008] The air filtration device can include an electric motor fordriving the impeller and a pair of electric prongs extending outwardlyfrom the rear surface of the housing for operational engagement with anelectrical wall outlet for supplying electric power to the electricmotor. The pair of electrical prongs can be configured with each prongin the pair having substantially the same dimensions, so that said airfiltration device may be connected to an electrical outlet withoutregard to the dimensional differences between the socket openings.

[0009] The air filtration device may further include an indicator forcommunicating that the filter should be changed, the indicator providinginformation after a predetermined period of operation of the airfiltration device has passed. The impeller may be driven electricallyand the indicator can include an electric timer circuit operationallyassociated with the impeller for determining when a predetermined timeof impeller operation has passed.

[0010] A lamp may be mounted to the housing for illumination when theimpeller is in operation, with the lamp being in electricalcommunication with the electric timer circuit and configured to providepulsating illumination when a predetermined time of impeller operationhas passed. A reset switch can be provided in electrical communicationwith the electric timer circuit to selectively reset the electric timercircuit to a zero operational time setting.

[0011] In an alternative embodiment of the present invention, theindicator may comprise an indicator member movably supported by thehousing. The indicator member most preferably includes a date wheelrotably supported by the housing and having an annular indicia ring.Indicia are supported by the annular indicia ring for selectiverotational positioning relative to the housing at one of a plurality ofset positions, wherein each indicia indicates time and is associatedwith one of the set positions. An indexing device is operably associatedwith the date wheel for rotationally and releasably retaining the wheelin one of the plurality of set positions. The rotational positioning ofthe date wheel relative to the housing provides an indication of whenthe filter should be replaced.

[0012] It will be understood by those skilled in the art that variationson that which is described above may be achieved by addition or omissionof the features of the features above described.

[0013] Accordingly, an air filtration device is provided for intake ofatmospheric air, assistance in removal of contaminants from theatmospheric air, expulsion of filtered air and configured foroperational association with a generally vertically oriented surface,and includes a housing for abutting attachment to an electrical outlet,the housing defining an air flow path therethrough and having a frontsurface, at least one side surface and a rear surface; at least one airinlet formed in the housing; at least one air outlet formed in thehousing intermediate the front surface and the rear surface; a filtermounted to the housing in the air flow path; an electrically drivenimpeller for moving air through the housing along the air flow path fromthe at least one air inlet to the at least one air outlet, with theimpeller being mounted to the housing; and a pair of electric prongsextending outwardly from the rear surface for operational engagementwith an electrical wall outlet for supplying electric power to theimpeller. The pair of electrical prongs can be configured with eachprong in the pair having substantially the same dimensions, so that saidair filtration device may be connected to an electrical outlet withoutregard to the dimensional differences between the socket openings. Abumper member is attached to the rear surface of the housing forabutment with a generally vertical surface to which the bumper membermay abut for orienting the device with the vertical surface. The bumpermay be formed from resilient material for damping vibrations receivedfrom the housing to provide enhanced noise reduction when the airfiltration device is in operation.

[0014] The air filtration device includes an air inlet that is formed onthe front surface of the housing and the air flow path is defined fromthe air inlet on the front surface through the filter, through theimpeller and outwardly through the air outlet. The filter may be formedas a generally planar member selectively removable from the housing andincludes a notch formed therein for directing insertion of the filter ina correct orientation with respect to the air flow path. The housing mayinclude a locating surface formed thereon and corresponding with thenotch in the filter to orient the filter in the housing. The housing mayinclude an icon formed at a position corresponding with the notch in thefilter when the filter is inserted in the housing for enhanced visualindication of proper filter orientation.

[0015] The air filtration device may include an indicator forcommunicating that the filter should be changed, the indicator providinginformation after a predetermined period of operation of the airfiltration device has passed. The impeller may be driven electricallyand the indicator may include an electric timer circuit operationallyengaged with the impeller for determining when a predetermined time ofimpeller operation has passed. The air filtration device also caninclude a lamp mounted to the housing for illumination when the impelleris in operation, the lamp being in electrical communication with theelectric timer circuit and configured to provide pulsating illuminationwhen a predetermined time of impeller operation has passed. A resetswitch can be provided in electrical communication with the electrictimer circuit to selectively reset the electric timer circuit to a zerooperational time setting. The indicator may alternatively comprise adate wheel rotatably supported by the housing and including indiciacomprising symbols indicative of time for providing an indication ofwhen the filter should be replaced.

[0016] It should also be understood that the above-described featuresmay be combined under a single, full-featured unit. In that regard, anair filtration device for intake of atmospheric air, removal ofcontaminants from the atmospheric air, expulsion of filtered air andconfigured for operational association with a generally verticallyoriented surface, includes a housing for abutting attachment to anelectrical outlet, the housing defining an air flow path therethroughand having a front surface, a curved side surface and a rear surface; atleast one air inlet formed in the front surface of the housing; and aseries of vents formed in the side surface intermediate the frontsurface and the rear surface, for cooperation of the vents with agenerally vertical surface to which the air filtration device isassociated for enhanced dispersion of filtered air expelled through thevents. A filter is mounted to the housing intermediate the at least oneair inlet and the at least one air outlet, with the filter being formedas a generally planar member selectively removable from the housing andincluding a notch formed therein for directing insertion of the filterin a correct orientation with respect to the air flow path. The housingmay include a locating surface formed thereon and corresponding with thenotch in the filter to orient the filter in the housing. An electricallydriven impeller is provided for moving air through the housing along theair flow path from the at least one air inlet to the vents, with theimpeller being mounted to the housing. A pair of electric prongs extendsoutwardly from the rear surface for operational engagement with anelectrical wall outlet for supplying electric power to the impeller. Thepair of electrical prongs can be configured with each prong in the pairhaving substantially the same dimensions, so that the air filtrationdevice may be connected to an electrical outlet without regard to thedimensional differences between the socket openings. A bumper member isattached to the rear surface of the housing for abutment with agenerally vertical surface to which the bumper member may abut fororienting the device with the vertical surface. The bumper member may beformed from resilient material for damping vibrations received from thehousing for enhanced noise reduction when the air filtration device isin operation.

[0017] The air filtration device may include an indicator providinginformation after a predetermined time period of operation of the airfiltration device has passed. The indicator may include an electrictimer circuit, as described above, to determine how long the impellerhas been in operation and, when the time period has passed, an indicatorlamp provides a pulsing illumination. The electric timer circuit mayalso be provided with a reset switch to selectively reset the electrictimer circuit to a zero operational time setting. Alternatively, theindicator may comprise a mechanical date wheel for manual rotationrelative to the housing, as described herein.

[0018] By the above, the present invention provides an air filtrationdevice that will plug directly into an outlet and utilize the wallbehind the device for dispersion of filtered air, while directing airintake from a central source. The present invention also provides ahandy visual indication of when the filter is placed in properorientation with respect to air flow. Further, the device providesreduced noise by damping vibrations transmitted from the housing to thewall against which the device is mounted. Finally, the present inventionprovides a filter change indicator for providing a convenient visualindication of when the filter should be replaced.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019]FIG. 1 is a perspective view of an air filtration device accordingto the preferred embodiment of the present invention;

[0020]FIG. 2 is a front view of the air filtration device illustrated inFIG. 1;

[0021]FIG. 3 is a rear view of the air filtration device illustrated inFIG. 1;

[0022]FIG. 4 is an exploded view of the air filtration deviceillustrated in FIG. 1;

[0023]FIG. 5 is a cross-sectional view of the air filtration devicetaken along line 5-5 in FIG. 2;

[0024]FIG. 6 is a cross-sectional view of the air filtration devicesimilar to the device in FIG. 5, illustrating an alternate embodimentwithout a timer circuit;

[0025]FIG. 7 is a side view of the air filtration device illustrated inFIG. 1, shown mounted to a wall;

[0026]FIG. 8 is a rear view of the air filtration device as illustratedin FIG. 3, shown mounted to a wall;

[0027]FIG. 9 is a front perspective view of the air filtration deviceillustrating filter placement;

[0028]FIG. 10 is a front perspective view of the air filtration deviceillustrated in FIG. 9, with the filter inserted properly;

[0029]FIG. 11 is a partial perspective view of the air filtration devicesimilar to the device in FIG. 1, illustrating an alternative embodimentof a filter change indicator;

[0030]FIG. 12 is a cross-sectional view of the air filtration devicetaken along line 12-12in FIG. 11;

[0031]FIG. 13 is a partial rear elevational view, with a partialcut-away, of the air filtration device of FIG. 11, illustrating thealternative embodiment of the filter change indicator; and

[0032]FIG. 14 is a partial exploded view of the filter change indicatorof FIG.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0033] Turning now to the drawings and, more particularly to FIGS. 1, 2and 3, an air filtration device for intake of atmospheric air,filtration of the atmospheric air and emission of filtered air isillustration generally at 10 and includes a housing 12. The housing 12includes a generally curved side wall 28 fixed to a generally flat frontportion 29. A generally planar door 18 is fixed to the flat frontportion 29, using hinges 19 as seen in FIG. 3. Referring back to FIG. 1,the door 18 includes a front surface 14 and a generally circularperforated air inlet grill 16. Tabs 20 are provided on each side of thedoor as seen in FIGS. 1 and 2, for ease of opening for filterreplacement, as will be seen in greater detail hereinafter. The doorcovers approximately 80% of the front surface of the device 10. Theremainder of the front surface is covered by a control panel 22. Thisratio is primarily a function of aesthetics, and does not effect theperformance of the device 10. A centralized rocker 24 is provided in thecontrol panel 22 to control an internal switch to activate anddeactivate the device 10 and an indicator light 26 is provided above therocker switch 24 which illuminates when the device 10 is activated and,as will be seen in greater detail hereinafter, flashes when thefiltration device 10 has been in operation for a predetermined timeperiod. A plurality of vents 30 are provided around the curved sidesurface 28 to act as air outlets.

[0034] Turning now to FIG. 3, a rear surface 32 is provided adjacent andintegral with the side surface 28. The rear surface 32 is curved toconform to the shape of the side surface 28.

[0035] In order to facilitate electrical power application, a pair ofelectrical prongs 34 extend outwardly from the rear surface 32 foroperational engagement with a conventional electrical outlet. Theelectric prongs 34 are each formed of like dimensions, so that the airfiltration device may be connected to an electrical outlet withoutregard to the dimensional differences between the socket openings.Accordingly, the device 10 may be oriented properly, with the prongs 34above the vents 30, no matter what orientation a polarized socket ismounted to the outlet E. Further, the prong arrangement allows thedevice 10 to be mounted in the lower of the two sockets in an outletpair, without regard to the dimensional differences between the socketopenings. The location of the prongs 34 with respect to the top of thehousing 12 ensures that the uppermost socket in a socket pair willremain available for use by other devices when the device 10 is inoperation, as seen in FIG. 8.

[0036] A bumper member 36 is provided below the electrical prongs 34 forabutment with a vertical surface or wall W against which the device 10is mounted, as seen in FIGS. 7 and 8. The bumper member 36 assists auser in orienting the device 10 with respect to a wall surface W.Further, the bumper member 36 may be formed from resilient material. Aresilient bumper member 36 absorbs and dampens vibrations from thehousing 12 to reduce or prevent their transmission to the wall W whichreduces the noise associated with an operational air filtration device10.

[0037] Turning now to FIGS. 4, 5 and 6, the internal components of thedevice 10 are illustrated. It will be appreciated that in order tofilter air, an air flow path is defined through the housing 12, a filter40 is provided and a device is provided to move the air. As seen in FIG.5, the air flow path, illustrated by arrows, is defined by air movementgenerated within the device 10, from the air inlet 16, through thedevice 10 and outwardly through the vents 30. An impeller 54 is providedto move air through the device 10. The impeller 54 is a basket-likestructure having two mounting rings 55 separated by a plurality of vanes57 that are curved to draw air from outside the impeller 54 and drivethe air outwardly through the side of the impeller 54.

[0038] The impeller 54 is rotated by an electric motor 46. As seen inFIG. 5, the motor 46 includes an armature 56 attached to the impeller54. Electrical excitation of the motor 46 causes the armature 56 torotate, thereby rotating the impeller 54.

[0039] As also seen in FIGS. 4, 5 and 6, a filter 40 is provided forfiltering incoming air. The filter 40 can be directional in that aparticular surface can be facing incoming air so that contaminated airis drawn through the filter 40 in a direction optimal for airfiltration. One useful filter 40 includes a front filtration surface 41,a rear scrim 43 and is charcoal activated. It will be appreciated bythose skilled in the filtration art that other filter compositions maybe used. In particular, some filters may be configured to removebathroom odors and some filters may be configured to remove kitchenodors. Other types of filters may include an increased charcoal contentfor smoke filtration. It is contemplated that various types of filtersmay be used with the present air filtration device 10 without reducingthe effectiveness of any of the filters or the overall filteringefficacy of the device 10. The filter 40 is formed with a notch 42 inone comer, as will be explained in greater detail hereinafter.

[0040] An internal baffle plate 60 is provided to provide a surface formounting the filter 40 and to direct air inwardly toward the impeller. Aconical inner surface 62 is provided in the baffle plate 60 to provide anozzle effect to increase the effectiveness of the filtration device 10.A locating surface 43 is formed as a raised rib in a lower comer of thebaffle plate 60 corresponding to the notch 42 in the filter 40 fororienting the filter in the housing 12. An icon 44 is applied to thebaffle plate 60 adjacent the locating surface 43, for visual indicationof proper filter orientation. As also illustrated in FIG. 4, the airfiltration device 10 is configured for mounting against an electricaloutlet E mounted on a wall W.

[0041] As seen in FIGS. 5 and 6, the air flow path is defined throughthe housing 12 and illustrated by arrows. Atmospheric air enters the airfiltration device 10 through the air inlet grill 16 and then travelsthrough the filter 40 for contaminant removal. With reference to FIG. 4,the air travels down the conical inner surface 62 fo the internal baffleplate 60 and enters a plenum 63 containing the rotating impeller 54. Theimpeller 54 draws the air along the flow path to an area within therotating vanes 57 and the air is directed then outwardly through therotating vanes 57 through the plenum 63 and eventually out through thevents 30 in the curved side wall 28.

[0042] Another feature of the present invention is a filter changeindicator providing the ability to determine in general when the filter40 should be replaced. Under normal operation, the filter 40 should bereplaced after a predetermined period of time. It may be presumed thatthe time period of filter contamination coincides with the operatingperiod of the impeller 54 and therefore the motor 46. In a firstembodiment of the filter change indicator, a timing circuit 48 isprovided in the wiring 50 that connects the switch 25 to the motor 46.As also seen in FIGS. 5 and 6, the rocker 24 operates a remotelydisposed switch 25, with the rocker 24 projecting through the controlpanel 22. It should be appreciated by those skilled in the art that sucha timing circuit is a basic electronic device and can be configured inany number of ways. The timing circuit is also in electricalcommunication with the indicator lamp 26 which illuminates uponelectrical excitation of the motor 46. When the timing circuit 48 hasreached the end of a predetermined time period, the indicator light 26is caused to pulsate, or flash, which is an indication that the filter40 should likely be replaced. The timing circuit 48 also includes areset switch 49 which allows an operator or owner to reset the timeronce the filter is replaced.

[0043] Optionally, the device 10 may be provided without a timingcircuit 48 as illustrated in FIG. 6. In such a case, a second ormechanical filter change indicator, as illustrated in FIGS. 11-14, maybe utilized. More particularly, an indicator member is movably supportedby the housing 12 and preferably comprises a date wheel 64 rotatablysupported intermediate the control panel 22 and the flat front portion29 of the housing 12. The date wheel 64 includes a substantiallycylindrical outer wall 66 defining a substantially annular indicia ring68 supported for rotation about a longitudinal center axis 69. Indicia70, preferably symbols representing months of the year arranged insuccessive chronological order, are supported on an outer surface 72 ofthe indicia ring 68. The outer wall 66 further defines a substantiallyannular gripping ring 74 includes disposed relative to the indicia ring68. The gripping ring 74 concludes a gripping surface, most preferablyin the form of a plurality of alternating projections 76 and recesses 78for providing improved frictional engagement or gripping of the datewheel 64 by a user and thereby facilitating rotational movement of thewheel 64.

[0044] A spacing wall 80 extends peripherally around the flat frontportion 29 of the housing 12 in a forward direction toward the controlpanel 20 and the door 18. The spacing wall 80 includes an upper portion82 having a viewing window 84 formed therein. A portion of the indiciaring 68 is visible through the viewing window 84 thereby permitting theuser to view a limited portion of the indicia 70 therethrough. A portionof the annular gripping ring 74 preferably extends upwardly through theviewing window 84 for facilitating engagement by a user. A pointer 86 ispreferably formed within an upper surface of a control panel 22 foralignment with one of the indicia 70, thereby facilitating reading ofthe appropriate symbol within the viewing window 84.

[0045] The date wheel 64 is rotatably supported on an axial 90 extendingrearwardly from an inner surface of the control panel 22. The axle 90passes through an aperture 92 formed within the baffle plate 60. Asemi-annular recess is formed within the baffle plate concentricallywith respect to the aperture 92 first guiding ring 96 extendingfrontwardly from the date wheel 64. As may be appreciated, receipt ofthe first guiding ring 96 within the recess 94 facilitates relativepositioning of the date wheel 64 relative to the baffle plate 60. Theaxle 90 is received within an aperture 98 formed within the date wheel64 concentrically relative to the outer wall 66.

[0046] An annular second guiding ring 100 extends rearwardly from thedate wheel 64 and is concentrically received within a counterbore 102formed within a post 104 extending forwardly from an inner surface ofthe front portion 29 of the housing 12. Receipt of the ring 100 withinthe bore 102 further assists in proper location of the date wheel 64within the housing 12. It should be further noted that a conventionalfastener, such as a screw 106, passes through a bore 108 in the post104, and is threadably received within a threaded bore 110 of the axle90. As such, the screw 106 secures the date wheel 64 and baffle plate 60intermediate the housing 12 and control panel 22.

[0047] An indexing device 112 is operably associated with the date wheel64 for rotationally and releasably retaining the date wheel 64 in one ofa plurality of set positions. The set positions are associated with theindicia 70 supported by the date wheel 64. In the preferred embodiment,each set position is associated with one of the symbols representing themonths of the year. The indexing device 112 includes a plurality ofradially outwardly extending indexing recesses 114 formed within asubstantially cylindrical inner wall 116. The inner wall 116 isconcentrically disposed within the outer wall 66. A resilient finger 118extends frontwardly from the inner surface of the front portion 29 ofthe housing 12 and is receivable within any one of a plurality ofindexing recesses 114 for releasably securing the date wheel 64 in oneof the set positions and preventing inadvertent rotation therefrom. Moreparticularly, the indexing finger 118 is biased radially outwardlyrelative to the inner wall 116 such that the finger 118 is securablewithin the recesses 114.

[0048] In operation, it may be readily appreciated that positioning ofthe date wheel 64 relative to the viewing window 84, and moreparticularly with respect to the pointer 86, alters the particularindicia 70 visible to the user. The user simply rotates the date wheel64 to a desired time as represented by the indicia 70 for projectedfilter replacement. The particular month appearing within the window 84serves to remind the user when the filter 40 requires replacement.

[0049] Referring now to FIGS. 7 and 8, in operation, the air filtrationdevice 10 of the present invention is plugged into an electrical outletusing electrical prongs 34 in a generally conventional manner. The rearsurface 32 of the housing 12 is closely adjacent to the electricaloutlet E and may abut the electrical outlet E. The bumper member 36abuts the wall W or outlet E or indeed, any vertical surface to whichthe device 10 may be fixed in order to provide proper orientation of thedevice 10 with respect to the wall surface W and, if the bumper member36 is resilient, to provide a damping effect for motor vibrations thatmay be transmitted from the housing 12 during operation. Once a device10 is against the wall W the rocker 24 is moved into an “on” position,which causes the switch 25 to provide electrical excitation to the motor46 which, in turn, causes the impeller 54 to rotate, thereby drawingatmospheric air inwardly through the air inlet grill 16. The atmosphericair is drawn through the filter 40, and is caused to travel along theair flow path as defined in FIGS. 5 and 6. As the air passes through thefilter 40 contaminants are removed and the filtered air travelsintermediate the vanes 57 of the impeller 54 and is expelled through thevents 30 formed in the curved side surface 28. As seen in FIG. 7, and aswill be appreciated by those skilled in the art, the filtered air isdispersed along an approximately 315° curve and the wall W acts as abaffle to enhance air dispersion from the device 10. Therefore, the airfiltration device 10 of the present invention draws air from a generallyfocused source of contaminated air and provides a dispersed wave offiltered air to enhance the effectiveness of the filter operation. Itshould be noted that the relationship of the device 10 and the wall LW,along with the vent location, is illustrated in FIG. 8.

[0050] As previously stated, the present invention provides a user withvisual enhancements with respect to filter replacement. With referenceto FIG. 9, a filter is shown spaced a distance from the baffle plate 60to which it is to be mounted. As can be seen, the filter 40 includes anotch 42 formed in a lower right hand comer of the filter 40. The baffleplate 60 includes the icon 44 which is preferably shaped as a keyhole,yet may be shaped in any configuration imaginable. By orienting thenotch 42 when the filter 40 is in place, as seen in FIG. 10, the filter40 is oriented properly with respect to air flow. Should the filter 40be inserted in a reverse manner, the icon 44 would not be visible,because the notch 42 would not be in a position to allow the user to seethe icon 44. Additionally, the locating surface 43 acts to physicallyorient the filter 40. Therefore, the combination of the notch 42, theicon 44, and the locating surface 43 allows someone replacing the filterto easily determine when the filter is in proper orientation withrespect to air flow.

[0051] By the above, the present invention provides a compact airfiltration device that provides enhanced effectiveness, the ability todetermine when a filter should be replaced, and a visual indication ofproper filter orientation with respect to air flow.

[0052] It will therefore be readily understood by those persons skilledin the art that the present invention is susceptible of a broad utilityand application. Many embodiments and adaptations of the presentinvention other than those herein described, as well as many variations,modifications and equivalent arrangements, will be apparent from orreasonably suggested by the present invention and the foregoingdescription thereof, without departing from the substance or scope ofthe present invention. Accordingly, while the present invention has beendescribed herein in detail in relation to its preferred embodiment, itis to be understood that this disclosure is only illustrative andexemplary of the present invention and is made merely for purposes ofproviding a full and enabling disclosure of the invention. The foregoingdisclosure is not intended or to be construed to limit the presentinvention or otherwise to exclude any such other embodiments,adaptations, variations, modifications and equivalent arrangements, thepresent invention being limited only by the claims appended hereto andthe equivalents thereof.

What is claimed is:
 1. An air filtration device for intake ofatmospheric air, removal of contaminants from the atmospheric air, andexpulsion of filtered air, said air filtration device comprising: ahousing defining an air flow path; an air inlet formed in said housing;an air outlet formed in said housing in spaced relation to said airinlet, said air flow path extending between said air inlet and said airoutlet; a filter located in said air flow path; and a filter changeindicator including an indicator member movably supported by saidhousing, indicia supported by at least one of said indicator member andsaid housing for selective positioning relative to the other of saidhousing and said indicator member at one of a plurality of setpositions, each said indicia indicating time and associated with one ofsaid set positions wherein the positioning of said indicator memberrelative to said housing provides an indication of when said filtershould be replaced.
 2. The air filtration device of claim 1 furthercomprising: an impeller for moving air through said housing along saidair flow path from said air inlet to said air outlet; and a motoroperably connected to said impeller.
 3. The air filtration device ofclaim 2 further comprising a pair of electric prongs extending outwardlyfrom said housing for operational engagement with an electrical walloutlet for supplying electrical power to said motor.
 4. The airfiltration device of claim 1 wherein said indicia comprise symbolsrepresenting months of a calendar year arranged in successivechronological order.
 5. The air filtration device of claim 1 whereinsaid indicator member comprises a wheel rotatably supported by saidhousing and including a peripheral outer surface supporting saidindicia.
 6. The air filtration device of claim 5 wherein said housingfurther includes a viewing window, a portion of said indicia supportedby said outer surface of said wheel visible through said viewing window.7. The air filtration device of claim 5 further comprising an indexingdevice operably associated with said wheel for releasably retaining saidwheel from rotational movement in one of said plurality of set positionsrelative to said housing.
 8. The air filtration device of claim 7wherein said indexing device comprises a resilient finger supported bysaid housing and a plurality of circumferentially spaced indexingrecesses formed within said wheel for receiving said finger.
 9. The airfiltration device of claim 5 wherein said wheel comprises an annularindicia ring defining said peripheral outer surface supporting saidindicia, and an annular gripping ring coaxlely disposed relative to saidindicia ring and including an outer peripheral surface having aplurality of alternating projections and recesses for facilitatinggripping of said wheel.
 10. An air filtration device for intake ofatmospheric air, removal of contaminants from the atmospheric air, andexpulsion of filtered air, said air filtration device comprising: ahousing; an air flow path extending within said housing; a filterlocated within said air flow path; a date wheel rotatably supported bysaid housing, said date wheel including an annular indicia ring havingan outer peripheral surface, indicia supported by said outer peripheralsurface for selective positioning relative to said housing at one of aplurality of set positions, each said indicia indicating time andassociated with one of said set positions; and an indexing deviceoperably associated with said date wheel for rotationally and releasablyretaining said wheel in one of said plurality of set positions, whereinthe positioning of said date wheel relative to said housing provides anindication of when said filter should be replaced.
 11. The airfiltration device of claim 10 wherein said indicia comprise symbolsrepresenting months of a calendar year arranged in successivechronological order.
 12. The air filtration device of claim 10 whereinsaid housing further includes a viewing window, a portion of saidindicia ring visible through said window.
 13. The air filtration deviceof claim 10 wherein said indexing device comprises a resilient fingersupported by said housing and a plurality of circumferentially spacedindexing recesses formed within said date wheel for receiving saidfinger.
 14. The air filtration device of claim 13 wherein said datewheel further includes a substantially cylindrical inner wall, saidindexing recesses extending substantially radially outwardly within saidinner wall, and said finger biased substantially radially outwardlyrelative to said inner wall for releasable engagement with said indexingrecesses.
 15. The air filtration device of claim 14 wherein said datewheel further comprises a substantially cylindrical outer wallconcentrically disposed relative to said inner wall, said indicia ringdefined by said outer wall.
 16. The air filtration device of claim 15wherein said date wheel further comprises an annual gripping ringdefined by said outer wall, said gripping ring including an outerperipheral surface having a plurality of alternating projections andrecesses for facilitating gripping of said wheel.